Credit: CourtesyBoston Celtics forward Paul Pierce, center, dunks as Cleveland Cavaliers forward LeBron James, left, and center Anderson Varejao of Brazil, right, watch during the second half of Game 4 in a second-round NBA basketball playoff series, Sunday, May 9, 2010, in Boston. The Celtics won 97-87, tying the series at 2-2. (AP Photo/Charles Krupa)

Paul Pierce was on the phone talking about his 2010 Celtics and the second-round series against Cleveland. He seemed to take particular joy in the video of LeBron James walking off the court in the Garden and removing his jersey on the way to the dressing room — the prelude to a departure for Miami two months later.

“We could be seeing history repeat itself,” Pierce said through laughter. “That’s the funny part about it, because if Boston beats them, we all know he’s gone. He may be gone anyway.”

Paul Pierce is an ESPN commentator these days, an unbiased provider of insight and opinions into the NBA. All of that is true, except for the unbiased part.

As the Celts renew acquaintances with the Cavaliers in these Eastern Conference finals, Pierce unapologetically wears his shamrock on his sleeve.

“I mean, they were our rivals,” he told the Herald. “You know, me and LeBron, we were like the top small forwards in the conference at the time, and it turned into a rivalry. We had a lot of good battles. That’s something that you just don’t forget. He’s one of the greatest players to ever play this game. I had a chance to take advantage of him for a couple of years, and after that you’ve seen his dominance. It’s nothing personal, but that’s what it was at the time.”

Pierce laughed again.

“I’m sure Isiah isn’t asking Jordan for hugs,” he said, recalling the old Detroit-Chicago wars featuring Thomas and Michael. “I’m sure he’s not praising Chicago on NBA TV. That’s just what it is. I’ll give credit where credit is due, but when you have a rival, it’s just hard to let go.”

In terms of credit, Pierce has much to send the way of these current Celtics. A little bit of shock, too. It’s fair to say that, like many others, he didn’t a deep playoff run in this club after Gordon Hayward went down on opening night and certainly when Kyrie Irving was lost for the remainder of the season in March.

“I’m more than surprised, man,” said Pierce. “The thing is, when Irving got hurt, I just thought, like, no chance. They’ll probably lose in the first round.

“But the surprising thing is how [Terry] Rozier has stepped up as a starter. You know, nobody knew how good that kid would be. And nobody knew how good [Jayson] Tatum would be. You knew he had potential, but you just didn’t know how well he’d step up in the playoffs. And then [Jaylen] Brown.

“For these guys to be so young and then be in the playoffs and then be in the Eastern Conference finals, that’s just helping them grow. It’s one of those deals where when you give a player confidence — and I give a lot of that credit to Brad Stevens — and that player has potential, that can grow into something special. And I think that’s what I think we’re witnessing right now with these guys. They’re getting tons of confidence, and they’re running with it. Even with the other guys gone, Brad’s putting these guys out there, and he’s expecting the same results. He expects these guys he puts out there to do great.”

So far, so great enough in this series. The Celtics maintained home-court advantage by winning the first two games, though with James and friends back in Cleveland, these next two could bring a shift in more than just venue.

But Pierce believes the Celts may actually have the Cavs’ number, so to speak. He sees a parallel to the way his 2010 squad looked at the James-centric Clevelanders.

“You’ve got LeBron, and he’s capable of carrying his team by himself, but the difficult thing about the Celtics is it’s hard to scout them,” said Pierce, who had his No. 34 retired in February the last time the C’s lost to the Cavs. “When you’ve got four or five guys who can beat you on any given night, that’s hard to play against. They share the ball and they play tough defense. That’s tough to scout.

“In 2010 when we played them down the stretch of the season when we were battling for seeding, we wanted to match up with Cleveland. We sat with Doc [Rivers] and talked about what seed we wanted. We said we wanted to get Cleveland in the second round, because we knew the way our defense was designed, we could beat a one-man team.

“Even though we didn’t have success with them during the regular season, when we got down to scouting them out, we felt like we had the advantage against Cleveland. And it looks like, right now, this is not a good matchup for Cleveland again. They’re lucky that Kyrie isn’t out there. If the role players don’t play well for Cleveland, they’re in trouble. A lot of things are really being put on the shoulders of Kevin Love to step up.”

Later, by the end of the conversation, Pierce was smiling through the phone again. His respect for the Cavaliers and LeBron is obvious, but the former Celtic captain seems to delight in the ability to play “the game” again. While he can no longer throw in dagger 3’s, he couldn’t resist a little good-natured trash talk.

“I hope the Celtics make it to The Finals,” Pierce needled, “because I don’t want to go to Cleveland. I’m tired of going to Cleveland for The Finals.”

He was laughing as he went, enjoying the rivalry once more. And that’s the unbiased Truth.